Flow diverting wind tunnel

ABSTRACT

A wind tunnel device is provided herein that enables the wind tunnel to transform between two modes of operation and/or to refresh/recondition air within the tunnel. The wind tunnel device may provide selective diversion of airflow within the wind tunnel. The diversion of airflow may enable the wind tunnel device to include a multi-configurable wind tunnel that can be operated as either an open-return wind tunnel or a closed-return wind tunnel. Additionally, or alternatively, the diversion of airflow may enable the wind tunnel device to recondition air within a closed-return wind tunnel.

TECHNOLOGICAL FIELD

This application relates to wind tunnel devices, and more particularlyto a flow diverting wind tunnel device.

BACKGROUND

Traditionally, wind tunnels are specifically designed as either anopen-return tunnel or a closed-return tunnel. Open-return wind tunnelsare designed such that the air traveling through the test section of thewind tunnel only passes one time through the measurement area andthereafter is expelled to the environment external to the wind tunnel(e.g., into the room or outdoors). In contrast, closed-return windtunnels are designed to continuously recirculate the airflow internallywithin the wind tunnel.

SUMMARY

A wind tunnel device is provided herein that enables selective diversionof airflow within the wind tunnel. The diversion of airflow may enablethe wind tunnel device to include a multi-configurable wind tunnel thatcan be operated as either an open-return wind tunnel or a closed-returnwind tunnel. In other words, the wind tunnel device may enable aclosed-return wind tunnel to function as an open-return wind tunnelwhile keeping the benefits of a closed system, and vice versa.Additionally, or alternatively, the diversion of airflow may enable thewind tunnel device to recondition the air within a closed-return windtunnel. In other words, the wind tunnel device may enable reconditioningof air inside the tunnel quickly without long downtimes. For example,the wind tunnel device may provide a flow path to refresh the airflowwithin the tunnel, effectively reconditioning the air (e.g., temperatureand/or humidity) within the tunnel. Accordingly, the wind tunnel deviceprovided herein can allow the wind tunnel to transform between two modesof operation and/or to refresh/recondition the air within the tunnel.

The wind tunnel device may use existing structure (e.g., infrastructure)of a closed-return wind tunnel to redirect the flow of the wind tunneland transform the flow path from a closed-return circuit to anopen-return circuit, and vice versa. Existing structure of aclosed-return wind tunnel includes, for example, corner turning vanesand a tunnel fan. The corner turning vanes may be actuateable betweenopen and closed positions, and the tunnel fan may be operable to actuatebaffles, such as dampers, to redirect the flow created by the tunnel fanfrom a closed-loop or recirculating design, into an open-loop design. Inthis form, the tunnel fan draws air from the outside, passes the airthrough the test section, and exhausts the air back outside.

According to one implementation, a wind tunnel device includes aclosed-loop tunnel, a fan positioned in the tunnel and configured tocirculate air through the tunnel, one or more movable members positionedin the tunnel, a supply duct selectively in fluid communication with thetunnel, and an exhaust duct selectively in fluid communication with thetunnel. The one or more movable members being movable between a firstposition in which the one or more movable members permit re-circulationof air through the tunnel and a second position in which the one or moremovable members inhibit re-circulation of air through the tunnel. Thesupply duct is configured to supply air to the tunnel and the exhaustduct is configured to permit air to flow out of the tunnel via the fanin response to the one or more movable members being moved to the secondposition.

According to another implementation, a method of operating a wind tunnelincludes re-circulating air through a tunnel via a fan positioned in thetunnel, moving one or more movable members positioned in the tunnel froma first position in which the one or more movable members permitre-circulation of air through the tunnel to a second position in whichthe one or more movable members inhibit re-circulation of air throughthe tunnel, supplying air to the tunnel via a supply duct in response tothe one or more movable members being moved to the second position, andpermitting air to flow out of the tunnel via an exhaust duct in responseto the one or more movable members being moved to the second position.

In yet a further implementation, a method of operating a wind tunnelincludes operating the wind tunnel as a closed-loop wind tunnel in whichair is re-circulated through the wind tunnel via a fan positioned in thewind tunnel and air is directed around a corner of the wind tunnel viaturning vanes, rotating the turning vanes to seal the corner of the windtunnel to inhibit re-circulation of air through the wind tunnel, andoperating the wind tunnel as an open-return wind tunnel in which airenters the wind tunnel via a supply duct and exits the wind tunnel viaan exhaust duct.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one embodiment of a wind tunnel deviceaccording to certain implementations.

FIG. 2 is a left side view of the wind tunnel device of FIG. 1.

FIG. 3 is a front view of the wind tunnel device of FIG. 1.

FIG. 4 is a right side view of the wind tunnel device of FIG. 1.

FIG. 5 is a top plan view of the wind tunnel device of FIG. 1.

FIG. 6 is a front left side view of the wind tunnel device of FIG. 1.

FIG. 7 is a view of an operating console that may be provided inconnection with the wind tunnel device of FIG. 1.

FIG. 8 is a schematic view of one embodiment of a wind tunnel device inan open-return configuration according to certain implementations.

FIG. 9 is a detail of multiple turning vanes of the wind tunnel deviceof FIG. 8 in an open position of the wind tunnel device in which theturning vanes are in a closed position to prevent airflow fromrecirculating.

FIG. 10 is a schematic view of the wind tunnel device of FIG. 8 in aclosed-return configuration.

FIG. 11 is a detail of multiple turning vanes of the wind tunnel deviceof FIG. 10 in a closed position of the wind tunnel device in which theturning vanes are in an open position and permit recirculation ofairflow.

DETAILED DESCRIPTION

Research has shown that the most reliable data for spray particleanalysis comes from using a wind tunnel to move fine spray particlesaway from an analysis device to prevent duplicate measurements. Thisdisclosure relates, in part, to low speed wind tunnels used for analysisof spray particle size.

Wind tunnel devices provided herein may provide for accurate laseranalysis of spray particles, which may be used for: product development(such as spray tip development); formulation development (such as activeingredients, e.g., herbicides, and adjuvants, e.g., drift reducercompositions); product label development; drift reduction technologydevelopment (e.g., spray tips, active ingredients and adjuvants); andgrower and applicator training and education. Wind tunnel devices mayaccordingly be configured to test a variety of herbicide activeingredients, adjuvants, spray tips, and combinations of these toevaluate potential off-target movement.

FIG. 1 shows a perspective view of one embodiment of a wind tunneldevice 10 according to certain implementations. The wind tunnel device10 may include a series of segments or sections. Each of the sectionsmay include a first end and a second end, such as a ceiling and a floor,respectively, as well as sidewalls therebetween. The sections may begenerally rectangularly shaped and open at two sides to enable thesections to be interconnected. Some of the sections may be configured ascorners and may include two open sides arranged at a right angle. Forexample, as shown in FIG. 1, the wind tunnel device 10 may include a fan12, a first section 14, a second section 16, and a third section 18. Thefan 12 and the three sections 14, 16, 18 may form a generallyrectangular footprint for containing the airflow. A tunnel 19 may bedefined within the volume enclosed within an interior defined by the fan12 and the three sections 14, 16, and 18 of the wind tunnel device 10and may enable airflow to pass therethrough. The tunnel 19 may becyclical such that a volume of airflow moves from the fan 12sequentially into the sections 14, 16, 18, and from section 18, theairflow may re-circulate back into the fan 12 without allowing thepassage of particulates or airflow to the exterior of the device.Providing a cyclical circuit enables the airflow to be reused, whichreduces the amount of air exiting the wind tunnel device 10 andminimizes particulate exposure. In some implementations, seals may beprovided between the sections to further minimize the possibility thatparticulates or circulating airflow will be transported outside the windtunnel device 10.

The fan 12 of the wind tunnel device 10 may include a motor 20configured to drive the fan 12, which may be communicatively coupled toa control system or an operating console of the wind tunnel device 10(see FIG. 7). In a particular embodiment, the fan 12 is manufactured byTwin City Fan M/N (TSL SW Model 542), and is of the inline centrifugaltype. As shown in FIGS. 1 and 5, the fan 12 may be joined to the firstsection 14 by a first duct 22 and to the third section 18 by a secondduct 24. In one embodiment, the motor 20 is a 7.5 horsepower motor thatmay be configured to generate wind speeds of between about 1 and 20miles per hour at a spray tip 25 (described below), or between about 1and 14 miles per hour. Those skilled in the art will appreciate that awide variety of commercially available fans with horsepower requirementsranging from 5 horsepower to 30 horsepower, or at about 5, 7.5, 10, 15,20, 25, 30 horsepower may be used in connection with the wind tunneldevice 10. Typically, the wind speed in the other portions of the flowcircuit defined by the wind tunnel device 10 is equal to that of thetest section, which is described further below in connection with thesecond section 12. However, in some implementations, flow may beexpanded through a portion of the flow circuit and may be contractedthrough a duct or other airflow control device upstream from the testsection.

The first section 14 of the wind tunnel device 10 may include a firstcorner 26, a first middle section 27 and second corner 28. As shown inFIGS. 1, 2 and 5, the first corner 26 may be joined to the second corner28 by way of the first middle section 27 and may form one side of thegenerally rectangular shape of the wind tunnel device 10. A portion ofthe tunnel 19 is formed within the volume enclosed by the first section14. As shown in FIGS. 1, 2, 3 and 5, each corner 26, 28 is generallyrectangular, may define a generally rectangular cross-section and maydefine openings at right angles relative to one another. As shown inFIG. 5, two adjacent sides of a corner 26, 28 form a generally rightangled surface at the exterior of the wind tunnel device 10. In order tolimit wind resistance due to such angles, each of the first and secondcorners 26 and 28 may include turning vanes 29 within an interior of thecorners 26, 28. The turning vanes 29 may be configured as verticallyextending members joined to top ends 26 a, 28 a and bottom ends 26 b, 28b of the first and second corners 26 and 28, respectively. In someimplementations, the turning vanes 29 may be configured as louvers oraerodynamic arcuately shaped vanes. In more specific implementations,the turning vanes 29 may be constant-arc vanes (e.g., high efficiencyprofile (HEP) turning vanes manufactured by Aerodyne). Other turningvane geometries may include, but are not limited to, single thicknesscircular arc designs, multiple thickness circular arc designs, singlethickness airfoil designs, and multiple thickness airfoil designs. Insome implementations, the turning vanes 29 may be spaced intermittentlyalong a diagonal line from the interior of the corner to the exterior ofthe corner 26, for example, extending between internal intersectionpoints where the outside exterior walls 26 c, 26 d meet and at whichinternal exterior walls 26 e, 26 f meet. The turning vanes 29 may beconfigured to provide minimum loss and disturbance of airflow as the airturns the corner channels. That is, the turning vanes 29 may be placedat generally right angled surfaces within the corners 26, 28 to reducewind resistance and direct airflow away from the right angled surfacesand some turning vanes 29 may be spaced apart within the corner 26, 28to more evenly direct the airflow. In some implementations, airflow maybe turned within the wind tunnel device without any turning vanes.

As shown in FIGS. 1, 3, 5 and 6, the second section 16 of the windtunnel device 10 may be configured as a generally rectangular cabinetand may define the test section 38. The test section 38 may join to thesecond corner 28 of the first section 14 and to a first corner 30 of thethird section 18. A portion of the tunnel 19 is formed within the volumeenclosed by the test section 38.

The test section 38 of the second section 16 may generally defineanother side of the rectangular shape of the wind tunnel device 10. Therectangular test section 38 may be configured to include a first portion39 with a honeycomb air stabilizer unit 40 (not shown), a traversing armhousing 42 with a traversing arm 43 holding the spray tip 25 (FIG. 6), asecond portion 44 with a first expansion cutout 45, a second expansioncutout 46, a laser mount 48 that may hold a laser 49, glass wallsections 50 and a spray particle scrubber 51. The test section 38 mayhave an area that is 6 feet high by 3 feet wide by 12 feet long. In someimplementations, the test section 38 may have various dimensions, andpreferably the test section includes a length of at least 36 inches, anda width and a height that are at least one meter.

The first portion 39 of the test section 38 may be configured toaccommodate movement of the traversing arm 43, described below. Inaddition, the first portion 39 may generally define a rectangular crosssection with a ceiling at the upper end 38 a of the test section 38, afloor at the lower end 38 b of the test section 38, and a pair ofopposing sidewalls arranged therebetween. In some implementations, glasswall sections 50 may be provided as the sidewalls of the first portion39.

The honeycomb stabilizer unit 40 may generally be placed at the entranceto the test section 38. For example, the honeycomb stabilizer unit 40may generally be positioned at the interface where the second corner 28of the first portion 14 joins to the rectangular test section 38. Theunit may include a honeycomb structure that allows air to pass throughthe structure, and may facilitate a more uniform and straight airflowfrom the second corner 28 into the test section 38. In one embodiment,the air stabilizer unit, or flow conditioner, may ensure bothstraightness and uniformity of the airflow as it passes the spray tip.The honeycomb stabilizer unit 40 may have a size and shape similar orthe same as a cross-section of the wind tunnel, and may include ahoneycomb structure with cells of various configurations. For example, aseries of hexagonally-configured cells may each have dimensions of about2 inches by about 0.25 inches. In addition to the hexagonal cellgeometry, the cells may have square and round geometries, and mayinclude cells sizes adapted for flow conditioning that may include athicknesses likely ranging between 1″ up to 4″×¼″, ⅜″, ½″, ¾″ and 1″.Materials that may be used to fabricate the cells may include, but arenot limited to, aluminum, polycarbonate, PVC, ABS, polypropylene,stainless steel, and titanium.

The traversing arm housing 42 may be joined at the first portion 39 at afirst end 38 a of the test section 38, as shown in FIGS. 1 and 3. Thetraversing arm housing 42 may be configured to guide the traversing arm43 into the space defined by the first portion 39 of the test section38. In some implementations, the traversing arm housing 42 may include atrack for guiding the traversing arm 43 and a seal arranged at anopening where the traversing arm 43 enters the test section 38. The sealbetween the housing 42 and the traversing arm 43 ensures sprayparticulates do not escape the test section during spraying and testing.

The traversing arm 43 may extend from the traversing arm housing 42 andmay receive the spray tip 25. In some implementations, the spray tip 25is offset from the traversing arm 43, for example by about 6 to 8inches. In this example, the spray tip 25 may be coupled to thetraversing arm 43 via a conduit such as a rigid conduit projectinghorizontally from the traversing arm 43 and fluidly coupled to the spraytip 25. In further implementations, the traversing arm 43 or the conduitis adapted for the interchangeable attachment of spray tips and mayinclude a supply line coupled to a fluid delivery system for deliveringfluid to the one or more spray tips joined thereto. The spray tip 25 maybe configured to emit a spray forming spray particulates, and the spraytip 25 may be selected from a variety of spray tips (e.g., nozzles) suchas those used in agricultural applications.

The traversing arm 43 may be controllably lowered and raised between thefirst end 38 a of the test section 38, which may be proximate a ceilingof the first portion 39 of the test section 38, and a second end 38 b ofthe test section 38, which may be proximate a floor of the first portion39. This movement may be through the use of a stepper motor (not shown),which moves the traversing arm 43 along the traversing arm housing 42.

In some implementations, the traversing arm 43 may be shaped similar toan airplane wing as shown in FIG. 6. For example, an airfoil shapedtraversing arm 43 produced by Carlson Aircraft. Some suitable airfoilshapes for the arm 43 may be symmetrical circular arc shapes,symmetrical polynomial generated shapes, symmetrical matched ellipseshapes, and symmetrical NACA (National Advisory Committee forAeronautics) airfoil shapes. The airfoil shape of the traversing arm 43may provide less disruption to the airflow within the test section 38.However, other shapes may also be used for the traversing arm 43. Infurther implementations, the traversing arm housing 42 and traversingarm 43 may be fully enclosed within the test section 38. In thisimplementation, the traversing arm 43 may move along the traversing armhousing 42 within the test section 38, which may further minimize thepossibility that particulates from the spray tip 25 will be transportedoutside the wind tunnel device 10.

The second portion 44 of the test section 38 may be configured as afully enclosed testing region of the test section 38 where the sprayparticulates are analyzed. The second portion 44 includes a firstexpansion cutout 45 and a second expansion cutout 46 protrudingoutwardly from the first and second ends 38 a, 38 b of the test section38 proximate a floor and a ceiling of the test section 38, respectively.The second portion 44 of the test section 38 with the expansion cutouts45, 46 accordingly defines a space with cutouts forming an angledceiling and an angled floor separated by sidewalls. The sidewalls of thesecond portion 44 may include the glass wall sections 50 in an areaproximate where the spray analysis is conducted, described below. Theconfiguration of the second portion 44 of the test section 38accommodates the spray angles provided by the spray tip 25 joined to thetraversing arm 43. In contrast, the space defined by the first portion39 of the test section 38 may be unable to accommodate the spray anglesprovided by the spray tips 25 due to height limitations. For example,because the first portion 39 of the test section 38 is configured toallow the traversing arm 43 to translate between the first and secondends 38 a, 38 b of the test section 38, angled spray emitted from thespray tip 25 may otherwise contact the first and second ends 38 a, 38 bof the cabinet 30, e.g., the first portion 39 may define an area that issmaller than an area covered by the angled spray particulates. Theexpansion cutouts 45, 46 downstream from the spray tips 25 areconfigured to minimize such contact by the spray particulates.

The expansion cutouts 45, 46 may be configured as a five wall expansionpiece with an opening for positioning over an opening in an upper orlower end 38 a, 38 b of the test section 38. Walls of the expansioncutouts 45, 46 include angled sides that define an expansion angle 52that is approximately equal to the widest spray angle emitted by thespray tip 25 used in connection with the traversing arm 43. In someimplementations the spray tip 25 may deliver a maximum spray angle of140° and the expansion cutouts 45, 46 may be configured to accommodatethis or other maximum spray angles. In some implementations, theexpansion angle for the cutout may be about 45°. However, the expansionangle may vary from about 10° to about 90°. The depth of the expansioncutouts may be about 12 inches, and the size of the rectangles cut intothe test section wall for receiving the expansion cutout may be about 12wide by about 48 inches long. In some implementations, the cutouts 45,46 may be configured with the same shape. The first expansion cutout 45may include a drip tray that prevents any spray that impinges on thetest section walls from dripping through the measurement area. Thesecond expansion cutout 46 may include a drain for draining thecollected liquid. In some implementations, the first expansion cutout 45may define a small opening that may generally be capped, which may allowfor a suction system to condition the flow past the first expansioncutout 45, for example.

The expansion cutouts 45 and 46 in combination with the second portion44 of the test section 38 may be configured to allow the spray from wideand narrow angle spray tips 25 to be analyzed within the second portion44 of the test section 38 without the spray bouncing off or collectingand dripping from the ceiling and the floor of the test section 38. Forexample, as a wide angle spray tip 25 is spraying a fluid (e.g., aherbicide) when it is at the top end 38 a of the test section 38, thespray pattern of the herbicide may follow one or both of the angledexpansion cutouts 45, 46 and the spray pattern may be allowed to flowalong the expansion cutouts 45, 46 and the second portion 44 so that thespray pattern may be analyzed by the laser 48 and the particulates mayexit the second portion 44. For example, the configuration of theexpansion cutout 45 may prevent some droplets from forming on theceiling of the first end 38 a of the test section 38 above the spacecovered by the laser 49 by allowing the droplets to pass into and out ofthe expansion cutout 45. Similarly, the expansion cutout 46 may beconfigured at an angle at the second end 38 b of the test section 38 toprevent splatter from the herbicide hitting the floor of the second end38 b of the test section 38 and enter the space covered by the laser 49by allowing the droplets to pass into and out of the expansion cutout46. The expansion cutouts 45, 46 may thus be configured to limitmeasurement errors due to errant drops (e.g., droplets that drip downfrom walls or bounce off of walls) passing through the laser path suchas preventing fluid drops from forming as a result of hitting theceiling or floor of the top and bottom ends 38 a, 38 b of the testsection 38 and entering the space covered by the laser 49. Further,while some particulates may contact the drip tray of the first expansioncutout 45, the drip tray may prevent drop formation and channel theparticulates downstream from the testing region thereby preventing suchdrops from falling in the space covered by the laser. Other particulatescontacting the second expansion cutout 46 may be collected and drained.

The laser mount 48 of the test section 38 may be positioned proximatethe second portion 44 of the test section 38 and may be configured toreceive a laser 49 or other analysis devices. The laser mount 48 may bemovable horizontally and/or vertically at least along the glass sections50 of the second portion 44 to enable the laser 49 to measure sprayparticulates from various types of spray tips. For example, some spraytips 25 may deliver a sheet of liquid from an orifice and the sheet maybreak apart into spray particulates at a certain distance away from theorifice of the spray tips 25. In this example, the laser mount 48 andthe laser 49 may be moved horizontally to a position along the secondportion 44 corresponding to a location downstream from the nozzle wherethe spray particulates form. In some implementations, the laser mount 48may translate horizontally from 0 to 24 inches from the spray tip, 2 to18 inches from the spray tip or any combination thereof. In someimplementations, the laser mount 48 may translate vertically while thespray tips remain stationary. While the analysis device described hereinis a laser, it will be appreciated that other analysis devices may beused such as video imaging.

The glass sections 50 of the test section 38 may be configured to enableanalysis, such as laser analysis, of the spray particulates withoutforming openings within the sidewalls of the test section 38. The glassused in the wind tunnel device 10 may be a ⅜″ nominal thickness,low-iron, annealed, soda-lime glass. Acceptable glass configurations forthe test section may include, but are not limited to, ¼″ nominalthickness, ⅜″ nominal thickness, and ¾″ nominal thickness, andsubstantially equivalent metric sized materials. Acceptable compositionsfor the glass may include, but are not limited to, soda-lime, low-ironsoda lime, and borosilicate. In some implementations, fused quartz andsapphire may be used in areas to where the laser analysis takes place.Low iron glass may be preferred due to its increased opticaltransmission. In addition, available tempers are annealed, strengthened,and tempered, but annealed glass is preferable due to its low opticaldistortion for the laser. Some installations may use tempered glass, forexample, as a safety precaution. By analyzing the spray particulateswithin an environment separate from the user and from the analysisdevice, analysis may be performed by the user without risking exposureto potentially harmful chemicals and the analysis device remains free ofspray particulates, which may facilitate avoiding inaccuratemeasurements. While providing glass sections 50 along sidewalls of thesecond portion 44 of the test section 38 is preferred, other areas ofthe test section 38 may also include glass sections. For example, asshown in FIG. 6, the first portion 39 of the test section 38 may includesidewalls formed of glass sections 50 such as optical glass wallsconfigured to enable the user to view movement of the traversing arm 43.In some implementations, the glass sections 50 may be hinged to allowaccess to the interior of the test section 38, for example, to allowattachment of spray tips 25 and maintenance.

A spray particle scrubber 51 of the test section 38 may be joinedbetween the second portion 44 of the test section 38 and the thirdcorner 30 of the third section 18. In some implementations, the sprayparticle scrubber 51 may be configured to collect the droplets exitingthe second portion 44 of the test section 38 and may prevent thedroplets from continuing through the tunnel 19 defined by the windtunnel device 10. With the use of a spray particle scrubber 51, the airmay be reused and provided to the fan 12, for example. In oneembodiment, the scrubber 51 may be configured as a mist extractor. Inanother embodiment, the scrubber 51 may be 99.7% effective at removingparticles greater than 5 μm diameter. For example, the spray particlescrubber 51 may use a series of angled channels to change the flow pathof the particles, allowing them to settle out and run down the channels,into the waste disposal unit.

As shown in FIG. 7, a computer 52 may be configured as an operatingconsole for the wind tunnel device 10 and may be communicatively coupledthereto. The computer 52 may include a processor, a memory and a networkconnection. In some implementations, the computer 52 may be used tooperate the traversing arm 43, the laser mount 48, the laser 49, a fluiddelivery system for delivering fluid to the spray tips 25 and so on. Forexample, using the computer 52, an operator may adjust the position ofthe laser mount 48 and the laser 49 horizontally and vertically. Thismay protect the laser 49 from being handled while readjusting andrepositioning the laser 49. In some implementations, the laser 49 may beoperated using proprietary Sympatec software, WINDOX provided on thecomputer 52. In addition, the computer 52 may be configured to controlthe traversing arm 43 to lower and raise the spray tip 25 joinedthereto. A traversing arm motor (not shown) may also be operated usingsoftware on the computer 52.

As shown in FIGS. 1 and 4, a control box 60 is mounted to the exteriorof the wind tunnel device 10 and may be used to control the wind speedand a waste pump (not shown). The control box 60 may be operated usingthe computer 52 or may be operated separately therefrom.

As shown in FIGS. 1, 4 and 5, the third section 18 of the wind tunneldevice 10 may include a third corner 30 and a fourth corner 32 connectedby a second middle section 34. As shown in FIG. 5, the third corner 30,the fourth corner 32, and the second middle section 34 may defineanother side of the generally rectangular shape of the wind tunneldevice 10. A portion of the tunnel 19 is formed within the volumeenclosed by the third section 18. Similar to the first and secondcorners, each of the third and fourth corners 30 and 32 may includeturning vanes 29. The third section 18 provides a connection between thefan 12 and the second section 16 to enable airflow to be re-circulatedwithin the wind tunnel device 10. In some implementations, an exhaustsystem may be joined to the third section 18 to provide for safe removalof vapors or other contents in the airflow prior to re-circulating theairflow to the fan 12.

The wind tunnel device 10 disclosed herein provides several advantagesover prior approaches. Because the device 10 is configured tore-circulate airflow, ambient air (e.g., air from an externalenvironment in varying climates) need not be pumped into the device 10from external sources, or at least a reduced amount of air is pumpedinto the device. For example, during summer and winter months whenambient temperatures are warm or cold, air within the device 10 may bereused, which avoid cooling and heating airflow prior to itsintroduction into the device 10. A further advantage provided by thedevice 10 is the ability to provide the laser in a separate environmentfrom the interior of the device. This prevents the laser from foulingfrom spray particulates. In addition, because the laser may be mountedto the laser mount 48, the laser may be moved to multiple positions,which is in contrast to prior approaches in which lasers were staticallymounted within a chemical hood. Yet another advantage provided by thedevice 10 is the ability to move the spray tip 25 within the device,including use of wide angle spray tips (110 to 140°) without fouling thetest section. This differs from prior approaches in which the spray tipis mounted in one position, which may be problematic for leveling.Another advantage of the device is that the fully enclosed test chamber,facilitated by the optically clear glass, allows safe testing of activepesticide products.

Implementation of Use

In one implementation of use, the fan 12 may be operated by the motor 20to force air through the tunnel 19 defined by the wind tunnel device 10.A spray tip 25 is attached to the traversing arm 43 of the test section38. A conduit system adapted to transport fluids delivers fluid to thespray tip 25 to be sprayed therethrough. In some implementations, fluidmay be forced to travel through the conduit system using an aircompressor, pumps and so on. For example, the fluid to be delivered tothe spray tip 25 may be tank mixed and pressurized within the tank, theconduit system or both. The conduit system may be coupled to a flowmeter in order to measure the flow rate and pressure of the fluidpassing therethrough prior to exiting the spray tip 25. In general, thespray tip 25 configuration determines the flow rate and the pressure ofthe exiting spray. The use of a flow meter provides confirmation thatthe fluid passing through the conduit system is moving properly, or sothat any pressure drops may be accounted for when analyzing the sprayexiting the spray tip 25. This enables the user to comply with ASAE/ANSIS572.1 test standard for quality control and size classification ofagricultural nozzles, which may vary in quality when purchased from themanufacturer.

Using a computer 52, the traversing arm 43 is vertically lowered andraised within the first portion 39 of the test section 38 so that thatspray tip 25 travels from the first end 38 a of the test section 38 tothe second end 38 b of the test section 38. A fluid, such as anherbicide, is sprayed and the airflow passes the spray tip 25 at between1 and 14 miles per hour. The spray tip 25 delivers spray at about a 110°spray angle, which may exit the spray tip in a vertical orientation.However, the spray angle delivered may exceed 140°, for example,depending on the spray tip and fluid sprayed therefrom.

The airflow carries spray particulates from the spray tip 25 into thesecond portion 44 of the test section 38 with the first and secondexpansion cutouts 45, 46. The expansion cutouts 45, 46 of the secondportion 44 may substantially prevent droplets from forming on theceiling above the space covered by the laser 49, and the expansioncutout 46 prevents droplets from bouncing off the floor and into thespace covered by the laser 49. In some cases, the spray area may belarger than the second portion 44 of the test section 38 with the firstand second expansion cutouts 45, 46, and may impinge upon the testsection floor and ceiling but the particulates may be collected in adrip pan and channeled away from the test section. Prior to measurementof the spray particulates, the computer 52 is used to position the laser49. The computer 52 is used to collect readings and determine particlesize, which may then be analyzed. In some embodiments, the analysis maybe used to classify the spray particle size as “Very Fine,” “Fine,”“Medium,” “Coarse,” and “Very Coarse.”

The spray particulate measurements primarily may be taken whiletraversing the arm vertically up or down. Generally, for full-patternanalysis, the spray pattern measured during the run must clear the lasermeasurement area, prior to and after the run. The laser analysis may betriggered by the spray entering the test area and stopped when the sprayexits the test area.

The spray can also be measured from a static position in a variety oforientations for other types of analysis. The wind tunnel device 10provided herein is particularly useful for identifying sprayparticulates of various sizes, including particulates having a sizelimit of less than 150 μm and less than 105 μm.

The wind tunnel device 10 provided herein, with the laser mount 48proximate the glass sections 50 of the second portion 44, along with theexpansion cutouts 45, 46, may enable the device 10 to deliver airflowpast the spray tip 25 at a speed of between about 1 and 14 miles perhour, which corresponds to low testing speeds. Using low testing speeds,the laser 49 may accurately detect the particle sizes of the sprayparticulates within the testing region.

In addition, the results of the laser 49 analysis may provide accurateresults because the expansion cutouts 45, 46 may prevent errant dropsfrom passing through the path of the laser, described above.

Providing glass sections 50 proximate the laser mount 48 enables thelaser 49 to analyze the spray particulates without the particulatescontacting the laser 49. Users of the wind tunnel device 10 are alsoprotected from exposure to the spray particulates due to the enclosedspace formed by the series of joined segments forming the wind tunneldevice 10.

The cyclical or rectangular shape of the wind tunnel device 10 furtherprovides a system that re-circulates airflow, as described above. There-circulated airflow entering the fan 12 may be clean using the sprayparticle scrubber 51 positioned downstream from the testing region 44and upstream from the fan 12.

Flow Diverting Wind Tunnel

Traditionally, wind tunnels are designed as either open-return orclosed-return wind tunnels. In open-return wind tunnels, air travelingthrough the test section only passes one time through the test sectionand is expelled to the environment external to the wind tunnel device(e.g., into the room or outdoors). In contrast, closed-return windtunnels continuously recirculate airflow internally within the windtunnel.

Referring to FIGS. 8 and 10, a flow-diverting or multi-configurable windtunnel device 60 is illustrated. The wind tunnel device 60 includessubstantially the same features and operation as wind tunnel device 10depicted in FIGS. 1-7. Accordingly, the preceding discussion of thefeatures and operation of the wind tunnel device 10, as depicted inFIGS. 1-7, should be considered equally applicable to wind tunnel device60 depicted in FIGS. 8 and 10, except as noted in the followingdiscussion pertaining to the wind tunnel device 60.

The wind tunnel device 60 illustrated in FIGS. 8 and 10 may beconfigurable as an open-return or closed-return wind tunnel. In FIG. 8,the wind tunnel device 60 is configured as an open-return or linear windtunnel in which air enters the tunnel 19, passes through the testsection 38 only once, and exits the tunnel 19. In FIG. 10, the windtunnel device 60 is configured as a closed-loop or recirculating windtunnel in which air continuously recirculates through the test section38.

Referring to FIG. 10, the flow-diverting wind tunnel device 60 isconfigured as a recirculating wind tunnel in which airflow (representedby arrows 62 in FIG. 10) is circulated through the test section 38 via afan 12. The fan 12 may be coupled with a motor 20 (see FIG. 5)configured to drive the fan 12. The motor 20 may be communicativelycoupled to a control system or an operating console of the wind tunneldevice 60 (see, e.g., control system/operating console in FIG. 7).

Recirculating wind tunnels typically include corner turning vanes forredirecting airflow around the corners of the wind tunnel. For example,as shown in FIG. 5, each of the corners 26, 28, 30, 32 of the windtunnel device 10 may include turning vanes 29. The turning vanes 29 maybe spaced intermittently along a diagonal line from the interior of eachrespective corner to the exterior of each respective corner. The turningvanes 29 may be configured to provide minimum loss and disturbance ofairflow as the airflows around the corner. The turning vanes 29 may beplaced within the corners to reduce wind resistance and direct airflowaway from the right angled surfaces of the corners to direct the airflowaround the corners.

Referring to FIG. 10, the wind tunnel device 60 includes rotatableturning vanes 64 in an upper left-hand corner of the wind tunnel 19. Theturning vanes 64 may be configured substantially the same as the turningvanes 29, except the turning vanes 64 are rotatable between an openposition (see FIGS. 10 and 11) and a closed position (see FIGS. 8 and9). In the open position depicted in FIGS. 10 and 11, the turning vanes64 function the same as the turning vanes 29 to facilitate airflowaround the corners of the wind tunnel 19 during re-circulation of airthrough the tunnel 19. In the closed position depicted in FIGS. 8 and 9,the turning vanes 64 create a blockage (e.g., a sealed wall) in thetunnel 19 that inhibits re-circulation of air through the tunnel 19. Inthe closed position, the turning vanes 64 may overlap one another toinhibit airflow from re-circulating through the tunnel 19. In someimplementations, the turning vanes 64 may rotate about 90 degrees totransition between the open and closed positions. The rotational rangeof the turning vanes 64 may vary depending on the design of the turningvanes 64.

In some implementations, the turning vanes 64 may be configured aslouvers or aerodynamic arcuately-shaped vanes. In more specificimplementations, the turning vanes 64 may be constant-arc vanes.Referring to FIGS. 9 and 11, a subset of the turning vanes 64 depictedin FIGS. 8 and 10 are illustrated for reference. The turning vanes 64each may include an arcuate or curved wall 66 that extends across thetunnel 19. In a closed position (see FIG. 9), the turning vanes 64 mayoverlap and contact one another to form a sealed interface that inhibitsre-circulating airflow through the tunnel 19. For example, asillustrated in FIG. 9, the curved walls 66 may overlap and contact oneanother to form the sealed interface. The turning vanes 64 may include arecess 68 formed in an end plate 70 of the vanes 64 (see FIG. 11) toprevent interference between the end plates 70 of adjacent closed vanes64 (see FIG. 9). In an open position (see FIG. 11), the turning vanes 64may be spaced apart from one another to permit airflow between the vanes64, and may be oriented within the corner of the tunnel 19 to facilitateairflow around the corner. For example, as illustrated in FIG. 11, thecurved walls 66 may be spaced apart from one another to permit airflowbetween the walls 66, and the curvature of the walls 66 may facilitateairflow around the corner. The geometry, spacing, and number of turningvanes 64 may vary depending on the design of the tunnel 19. In oneembodiment, a spacing to chord ratio (s/c) of the vanes 64 is about 40percent.

The turning vanes 64 may be joined together to facilitate simultaneousrotation of the vanes 64. As illustrated in FIGS. 9 and 11, the turningvanes 64 may include tabs 72. The tabs 72 may be connected together viaa rod or other elongate member capable of rotating the vanes 64 inunison. In some implementations, the tabs 72 may define aperturestherein to facilitate interconnection of the vanes 64. Rotation of theturning vanes 64 may be controlled by a computer 52 (see FIG. 7), whichmay control an actuator coupled to the turning vanes 64.

Referring to FIGS. 8 and 10, the wind tunnel device 60 may be configuredto have an open-loop tunnel or a closed-loop tunnel depending on theposition of the turning vanes 64. The turning vanes 64 may be rotatableto either partition-off or redirect the flow of the tunnel 19, therebytransforming the flow path from a closed-return circuit (FIG. 10) to anopen-return circuit (FIG. 8), and vice versa. As illustrated in FIG. 10,when the turning vanes 64 are open, the tunnel 19 forms a closed loop inwhich airflow 62 re-circulates through the tunnel 19. As illustrated inFIG. 8, when the turning vanes 64 are closed, the tunnel 19 forms anopen loop in which airflow 62 only passes once through the test section38 of the tunnel 19.

In addition to actuating interior turning vanes 64, baffles or dampers(referenced herein as “dampers” for the sake of simplicity and withoutintent to limit) associated with external ductwork may be actuated toredirect the flow from a closed-loop or recirculating design (see FIG.10) into an open-loop condition (see FIG. 8), and vice versa. Thedampers may be positioned on both sides of the turning vanes 64. Forexample, a first set of dampers 74 may be positioned on a downstreamside of the turning vanes 64 and a second set of dampers 76 may bepositioned on the upstream side of the turning vanes 64. The dampers 74,76 may be associated with external ductwork in fluid communication withoutside air. For example, the dampers 74 may be associated with a supplyduct 78 configured to supply air (represented by arrows 80 in FIG. 8) tothe tunnel 19. The dampers 76 may be associated with an exhaust duct 82configured to permit airflow (represented by arrows 84 in FIG. 8) out ofthe tunnel 19.

The dampers 74, 76 may be biased toward a closed position (see FIG. 10)in which the dampers 74, 76 inhibit airflow between the tunnel 19 andthe ducts 78, 82. For example, a biasing element (such as a spring) maybias the dampers 74, 76 into the closed position to seal the ducts 78,82. The airflow generated by the fan 12 may be sufficient to move thedampers 74, 76 into an open position (see FIG. 8) when the turning vanes64 are closed. As such, during operation of the wind tunnel device 60,the fan 12 may continuously run. To switch the operating mode of thewind tunnel device 60, the turning vanes 64 can be rotated and then thedampers 74, 76 are closed (e.g., via a biasing element) or opened (e.g.,via the fan 12). For example, when the operating mode of the wind tunneldevice 60 is switched from a closed-loop configuration to an open-loopconfiguration, the turning vanes 64 are rotated into a closed positionand inhibit re-circulation of airflow through the tunnel 19, and thusthe airflow of the fan 12 opens the dampers 74 in the supply duct 78 andthe dampers 76 in the exhaust duct 82. When the operating mode of thewind tunnel device 60 is switched from an open-loop configuration to aclosed-loop configuration, the airflow of the fan 12 is allowed tore-circulate through the tunnel 19, and thus the bias of the dampers 74,76 causes the dampers 74, 76 to close.

When the wind tunnel device 60 is being operated in a closed operatingmode (see FIG. 10), the turning vanes 64 are opened and the dampers 74,76 are closed to form a fully-closed loop tunnel 19. In thisconfiguration, the wind tunnel device 60 functions as a re-circulatingwind tunnel. Airflow 62 generated by fan 12 may pass through atemperature control unit 86, which may be coupled to a chilled watersupply 88. After the temperature control unit 86, the airflow 62 maypass through the test section 38, into the scrubber 51 (such as a mistextractor), and back to the fan 12. Droplets collected by the scrubber51 may enter a waste disposal unit, which may include drains line 90, afresh water line 92, a liquid trap 94, a hazardous waste tank 96, and alab waste line 98.

When the wind tunnel device 60 is being operated in a closed-loopconfiguration (FIG. 10), the re-circulated air may need to berefreshed/reconditioned (referenced herein as “reconditioned” for thesake of simplicity and without intent to limit) after a period ofoperation. To recondition the air in the tunnel 19, the wind tunneldevice 60 may be reconfigured into the open-loop configuration (FIG. 8)for a short period of time, and then the wind tunnel device 60 may bereconfigured back into the closed-loop configuration (FIG. 10) whilecontinuously operating the wind tunnel device 60. In this manner, theconfiguration illustrated in FIG. 8 may be referred to as a purge modein which the air inside the test section 38 of the tunnel device 60 maybe reconditioned rapidly. Reasons to recondition the air in the tunnel19 may include reducing humidity levels in the tunnel 19 (especially forspray wind tunnels), reducing temperature in the tunnel 19, and reducingvapor content (e.g., pesticides) in the tunnel 19. By intermittentlyoperating the wind tunnel device 60 in an open-loop configuration (FIG.8), the air inside the tunnel 19 may be reconditioned rapidly by suckingin new air and forcing out old air. Alternatively, the wind tunneldevice 60 may be maintained in the open-loop configuration (FIG. 8) foropen-loop tunnel testing.

When the wind tunnel device 60 is being operated in an open-loopoperating mode (see FIG. 8), the turning vanes 64 are closed and thedampers 74, 76 are opened to form an open-loop tunnel 19. In thisconfiguration, the fan 12 draws air from outside the tunnel 19, passesthe air through the test section 38, and exhausts the air back outsidethe tunnel 19. More specifically, the fan 12 draws outside air into thetunnel 19 through the supply duct 78 and forces air out of the tunnel 19through the exhaust duct 82. Airflow 62 generated by fan 62 may enterthe tunnel 19 from the supply duct 78, pass through the temperaturecontrol unit 86. After the temperature control unit 86, the airflowpasses through the test section 38 into the scrubber 51 (such as a mistextractor), and back to the fan 12. Droplets collected by the scrubber51 may enter the waste disposal unit, which may include drain lines 90,the fresh water line 92, the liquid trap 94, the hazardous waste tank96, and the lab waste line 98.

By manipulating the turning vanes 64 and the dampers 74, 76, the windtunnel device 60 may function as a multi-use, multi-mode wind tunneldevice. In other words, the wind tunnel device 60 may transform betweentwo modes of operation, and the air within the tunnel 19 may bereconditioned during operation of the wind tunnel device 60.

The wind tunnel device 60 may enable a closed-return wind tunnel tomimic an open-return wind tunnel, while still keeping the benefits of aclosed system, and vice versa. In other words, the wind tunnel device 60may provide two-tunnels in one: an open return wind tunnel and a closedreturn wind tunnel. Additionally, or alternatively, the wind tunneldevice 60 may enable reconditioning of the air inside the tunnel 19quickly without long downtimes. The wind tunnel device 60 may beapplicable for users in atmospheric/sprays wind tunnel research, as wellas generally for users in agriculture, aerospace, and aerodynamics,among others.

Existing infrastructure of closed-return wind tunnels may be used toform the reconfigurable wind tunnel device 60. For example, a windtunnel device (such as wind tunnel device 10) may be configured as amulti-use, multi-mode wind tunnel device 60 by converting one or moresets of corner turning vanes 29 into rotating turning vanes 64 and byincluding supply and exhaust ducts 78, 82 with dampers 74, 76,respectively, that are operable via a tunnel fan (such as fan 12).

Although the present disclosure provides references to preferredembodiments, persons skilled in the art will recognize that changes maybe made in form and detail without departing from the spirit and scopeof the invention. For example, although the reconfigurable wind tunneldevice is described with rotating turning vanes, the reconfigurable windtunnel device may include other rotatable members (such as baffles,dampers, and other members capable of rotating between an open positionin which the members permit re-circulation of air through the tunnel anda closed position in which the members inhibit re-circulation of airthrough the tunnel. Similarly, the reconfigurable wind tunnel device mayinclude members that slide or otherwise move between an open position inwhich the members permit re-circulation of air through the tunnel and aclosed position in which the members inhibit re-circulation of airthrough the tunnel.

The invention claimed is:
 1. A wind tunnel device comprising: aclosed-loop tunnel that forms a generally rectangular path; a fanpositioned in the tunnel, the fan configured to circulate air throughthe closed-loop tunnel; one or more turning vanes positioned in a cornerof the tunnel and configured to move between a first position in whichthe one or more turning vanes permit re-circulation of air through thetunnel and a second position in which the one or more turning vanesinhibit re-circulation of air through the tunnel; a supply ductselectively in fluid communication with the tunnel; and an exhaust ductselectively in fluid communication with the tunnel; wherein the supplyduct is configured to supply air to the tunnel and the exhaust duct isconfigured to permit air to flow out of the tunnel via the fan inresponse to the one or more turning vanes being moved to the secondposition.
 2. The device of claim 1, wherein the one or more turningvanes define a curved contour configured to direct air around a cornerof the closed loop tunnel.
 3. The device of claim 1, wherein: the supplyduct is coupled with a first exterior wall of the corner; and theexhaust duct is coupled with a second exterior wall of the corner suchthat the one or more turnings vanes are arranged to extend between thesupply duct and the exhaust duct.
 4. The device of claim 1, wherein theone or more turning vanes comprise multiple rotating vanes spacedintermittently along a diagonal line from a first end of the corner to asecond end of the corner.
 5. The device of claim 4, wherein in thesecond position, adjacent vanes of the multiple rotating vanes areconfigured to form an air-tight seal with each other to inhibitre-circulation of air through the tunnel.
 6. The device of claim 4,wherein in the second position, adjacent vanes of the multiple rotatingvanes are configured to overlap each other.
 7. The device of claim 4,wherein in the first position, the multiple rotating vanes arepositioned to reduce wind resistance and direct airflow around thecorner.
 8. The device of claim 4, wherein in the first position, themultiple rotating vanes include an arcuate shape configured to reducewind resistance and direct air around the corner.
 9. The device of claim1, wherein the position of the one or more turning vanes is controlledvia a computer.
 10. The device of claim 1, wherein the supply duct isselectively in fluid communication with the tunnel via one or moredampers biased toward a closed position and configured to open to supplyair to the tunnel in response to the one or more turning vanes beingmoved to the second position.
 11. The device of claim 1, furthercomprising a temperature control unit positioned at least partially inthe tunnel; wherein the supply duct is in fluid communication with thetunnel between the one or more turning vanes and the temperature controlunit.
 12. The device of claim 1, wherein the exhaust duct is selectivelyin fluid communication with the tunnel via one or more dampers biasedtoward a closed position and configured to open to permit air to flowout of the tunnel in response to the one or more turning vanes beingmoved to the second position.
 13. The device of claim 1, wherein theexhaust duct is in fluid communication with the tunnel between the fanand the one or more turning vanes.
 14. A method of operating a windtunnel comprising: re-circulating air through a tunnel via a fanpositioned in the tunnel; moving one or more turning vanes positioned ina corner of the tunnel from a first position in which the one or moreturning vanes permit re-circulation of air through the tunnel to asecond position in which the one or more turning vanes inhibitre-circulation of air through the tunnel; supplying air to the tunnelvia a supply duct in response to the one or more turning vanes beingmoved to the second position; and permitting air to flow out of thetunnel via an exhaust duct in response to the one or more turning vanesbeing moved to the second position.
 15. The method of claim 14, furthercomprising forming an air-tight seal via the one or more turning vanesin the second position to inhibit re-circulation of air through thetunnel.
 16. The method of claim 14, wherein the one or more turningvanes comprise multiple rotating vanes; and further comprisingoverlapping the multiple rotating vanes in the second position toinhibit re-circulation of air through the tunnel.
 17. The method ofclaim 14, further comprising: opening one or more dampers associatedwith the supply duct via the fan to supply air to the tunnel via thesupply duct in response to the one or more turning vanes being moved tothe second position; and opening one or more dampers associated with theexhaust duct via the fan to permit air to flow out of the tunnel via theexhaust duct in response to the one or more turning vanes being moved tothe second position.
 18. The method of claim 14, wherein the tunnelforms a rectangular path.
 19. A method of operating a wind tunnelcomprising: operating the wind tunnel as a closed-loop wind tunnel inwhich air is re-circulated through the wind tunnel via a fan positionedin the wind tunnel and air is directed around a corner of the windtunnel via turning vanes adapted to minimize fluid resistance at thecorner; rotating the turning vanes to seal the corner of the wind tunnelto inhibit re-circulation of air through the wind tunnel; and operatingthe wind tunnel as an open-return wind tunnel in which air enters thewind tunnel via a supply duct and exits the wind tunnel via an exhaustduct.
 20. The method of claim 19, further comprising opening one or moredampers associated with the supply duct and the exhaust duct via the fanin response to rotating the turning vanes.